[petsc-users] questions

[Mike McCourt]

In order to use VecLoad, the binary file should have been generated by VecView:

http://www.mcs.anl.gov/petsc/snapshots/petsc-current/docs/manualpages/Vec/VecView.html#VecView

because there is information needed by PETSc to create a vector that you cannot provide independently.  There are several formats for inputting a vector into PETSc, but unfortunately, I don't think you can roll your own binary file.

-Mike

----- Original Message -----
From: "xiaohl" <xiaohl at ices.utexas.edu>
To: "PETSc users list" <petsc-users at mcs.anl.gov>
Sent: Thursday, November 17, 2011 1:55:14 PM
Subject: Re: [petsc-users] questions

 Hi Mike

 I created the binary file from a ASCII file by C.
 How could I create a file which I could use for petsc with DM routine?

 Hailong



 This is complaining that what is stored in that file is not a vector.  
 How was that binary file created?

 -Mike

 ----- Original Message -----
 From: "xiaohl" <xiaohl at ices.utexas.edu>
 To: "PETSc users list" <petsc-users at mcs.anl.gov>
 Sent: Thursday, November 17, 2011 1:08:39 PM
 Subject: Re: [petsc-users] questions

  Hi

  I got the error
  [0]PETSC ERROR: --------------------- Error Message
  ------------------------------------
  [0]PETSC ERROR: Invalid argument!
  [0]PETSC ERROR: Not a vector next in file!

  from the line "ierr = VecLoad(u,viewer); CHKERRQ(ierr);"

  Here is my code
  Vec u;
  ierr =
  DMDACreate3d(PETSC_COMM_WORLD,DMDA_BOUNDARY_NONE,DMDA_BOUNDARY_NONE,
  		      DMDA_BOUNDARY_NONE,DMDA_STENCIL_STAR,-4,-4,-4,
  		      PETSC_DECIDE,PETSC_DECIDE,PETSC_DECIDE,1,1,
  		      PETSC_NULL,PETSC_NULL,PETSC_NULL,&da); CHKERRQ(ierr);
  ierr = DMGetGlobalVector(da,&u); CHKERRQ(ierr);
  ierr =
  
 PetscViewerBinaryOpen(PETSC_COMM_WORLD,"permX.bin",FILE_MODE_READ,&viewer);CHKERRQ(ierr);
  ierr = VecLoad(u,viewer); CHKERRQ(ierr);

  I just followed the example
  
 "http://www.mcs.anl.gov/petsc/snapshots/petsc-dev/src/dm/examples/tutorials/ex9.c.html"
  Do you know what happened?

  Hailong







 On Wed, 2 Nov 2011 15:53:27 -0500, Barry Smith <bsmith at mcs.anl.gov> 
 wrote:
> On Nov 2, 2011, at 3:42 PM, Matthew Knepley wrote:
>
>> On Wed, Nov 2, 2011 at 8:38 PM, xiaohl <xiaohl at ices.utexas.edu> 
>> wrote:
>> Hi
>>
>> I am going to implement cell center difference method for
>> u = - K grad p
>> div u = f
>> where p is the pressure , u is the velocity, f is the source term.
>>
>> my goal is to assemble the matrix and test the performance of 
>> different linear solvers in parallel.
>>
>> my question is how can I read the input file for K where K is n*n 
>> tensor.
>>
>> MatLoad()
>
>    Hm, I think you should use a DMDA with n*n size dof and then use
> VecLoad() to load the entries of K.
>
>    Barry
>
>>
>> second one is that do you have any similar examples?
>>
>> Nothing with the mixed-discretization of the Laplacian.
>>
>>    Matt
>>
>> Hailong
>>
>>
>>
>> --
>> What most experimenters take for granted before they begin their 
>> experiments is infinitely more interesting than any results to which 
>> their experiments lead.
>> -- Norbert Wiener